The present invention relates generally to a system for driving an electric automotive vehicle and more particularly, to a system for controlling motors of the electric automotive vehicle.
JP-A 1-291603 discloses one prior art system for driving an electric automotive vehicle which includes a plurality of motor speed sensors for detecting a plurality of motors, respectively, and wherein even if any one of the plurality of motor speed sensors falls into malfunction, motor control can be continued by automatically separating it from a control system.
On the other hand, collected papers, article S9-3, published by DENKI GAKKAI (Electric Society of Japan) in 1991 in Japan, depicts sensorless control which is motor control without any motor speed sensor.
However, motor control as disclosed in JP-A 1-291603 has only one kind of input information, i.e. actual motor rotational speeds. Thus, if the actual motor rotational speeds cannot be obtained, motor control becomes divergent control and not convergent control such as feedback control, resulting in difficult maintenance of both responsibility and efficiency at a high level.
Likewise, sensorless control as depicted in the collected paper, article S9-3, belongs to divergent control, resulting in difficult maintenance of both responsibility and efficiency at a high level.
It is, therefore, an object of the present invention to provide a system for driving an electric automotive vehicle having excellent responsibility and efficiency, and sufficient reliability.